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19 Jan 2022 06:21:35 EST (-0500)
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From: William F Pokorny
Subject: Re: Proposed informational table for tiling pattern section.
Date: 26 Sep 2016 05:38:57
Message: <57e8ecb1$1@news.povray.org>
On 09/25/2016 07:45 PM, Jim Holsenback wrote:
> On 9/25/2016 6:03 PM, clipka wrote:
>> Am 25.09.2016 um 22:37 schrieb Jim Holsenback:
>>> On 9/25/2016 4:23 PM, Jim Holsenback wrote:
>>>> attached is modified file ...
>>>
>>> that i'll teach me to do it from memory ... attached is corrected
>>> version .... #case (1) | #case (2) NOT #case (1|2)
>>
>> Actually it should be `#case (1) #case (2)`. Nothing in between. If
>> you use
>>
>>     #case (1)
>>       ANYTHING
>>     #case (2)
>>       WHATEVER
>>     #break
>>
>> you'll effectively get `ANYTHING WHATEVER` for a value of 1, and
>> `WHATEVER` for a value of 2.
>
> doh ... tested with 2nd case and it passed. when i changed to 1st case
> it belched on |
>
> attached is repaired version

Not opposed to adding the information in the tiling.pov example.

I am opposed to this additional line in the example:

scale TileScale

which will distort what users see when exploring the tiling patterns.

Perhaps make it a comment :

// scale TileScale   // Unit square scale for this pattern if needed.

thought I recommend deleting the line.

Folks need to know the unit tile scale if wrapping the tiles around a 
cylinder or doing something like Jaime's wallpaper technique. Just 
setting up the switch is enough to provide the information assuming 
there is a mention in the documentation that is where the information 
is.

I'm also a little unsure of the new additional scale up of <5,1,5> 
you've added just below. Feels large. Does it look OK with all 27 tiling 
patterns?

Aside: There will be a similar set of 3 scalings for the pavement 
pattern, but I've just put in a pull request to add a pavement.pov 
example - so I'll go modify that pull request now instead of proposing 
wiki updates.

Will you be putting in the tiling.pov pull request yourself, or would 
you like me to do it?

Bill P.


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From: omniverse
Subject: Re: Proposed informational table for tiling pattern section.
Date: 26 Sep 2016 05:55:00
Message: <web.57e8efc1240564e0b1933f770@news.povray.org>
Jim Holsenback <spa### [at] nothanksnet> wrote:
> On 9/25/2016 6:03 PM, clipka wrote:
> > Am 25.09.2016 um 22:37 schrieb Jim Holsenback:
> >> On 9/25/2016 4:23 PM, Jim Holsenback wrote:
> >>> attached is modified file ...
> >>
> >> that i'll teach me to do it from memory ... attached is corrected
> >> version .... #case (1) | #case (2) NOT #case (1|2)
> >
> > Actually it should be `#case (1) #case (2)`. Nothing in between. If you use
> >
> >     #case (1)
> >       ANYTHING
> >     #case (2)
> >       WHATEVER
> >     #break
> >
> > you'll effectively get `ANYTHING WHATEVER` for a value of 1, and
> > `WHATEVER` for a value of 2.
>
> doh ... tested with 2nd case and it passed. when i changed to 1st case
> it belched on |
>
> attached is repaired version

First of all, thanks for supplying this test of the tiling pattern. I wasn't
aware of it, or had long since forgotten.

Something I was looking at by using that scene file was to find out how those
patterns would repeat as, well, tiles. Noticing you were rotating the original
tile to make 4 instances I wanted to see them side by side without rotation.

I replaced the scaling of box texture with the following, commenting out the
rotated boxes to put in moved boxes. I used animation to create the series of
images, which is why frame_number is here. That was put into the TilingPattern
declare also. Here's the other change at end of the box object:

#if (frame_number=19|frame_number=20)
scale TileScale /* no differences of tiling pattern 19 and 20 at this scale */
#else // some other scales do not tile repeatedly
scale TileScale/2 /* other patterns tile repeatedly except Penrose 25, 26 and 27
*/
#end
  }
  scale <5,1,5>
} // box

object {TestCase} // about to move tiles around, not rotate
object {TestCase translate <-5,0,0>}
object {TestCase translate <-5,0,-5>}
object {TestCase translate <0,0,-5>}

/*
#local YDir = 0;
#while (YDir < 360)
  object {TestCase rotate y*YDir}
  #declare YDir = YDir + 90;
#end
*/

Now a quandary about those 19 and 20 patterns. Apparently they each track
somewhat opposite (not exact) directions but are seen as identical with this
particular scale of just TileScale, the original. However it can be seen if
scaled smaller, except not able to repeat from what I've seen. I already tried
mirroring, too, but maybe not enough things to discover the repeating pattern
for individual tiles.

Had me thinking it might be one of those Penrose patterns before I realized
those were said to be the last three. Of course I don't know what any of these
are really, besides interesting!

And this was a good opportunity to say thanks to everyone still working on the
POV-Ray stuff.

Bob


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From: Jim Holsenback
Subject: Re: Proposed informational table for tiling pattern section.
Date: 26 Sep 2016 07:15:15
Message: <57e90343$1@news.povray.org>
On 9/26/2016 5:38 AM, William F Pokorny wrote:
> Not opposed to adding the information in the tiling.pov example.
>
> I am opposed to this additional line in the example:
>
> scale TileScale
>
> which will distort what users see when exploring the tiling patterns.
>
> Perhaps make it a comment :
>
> // scale TileScale   // Unit square scale for this pattern if needed.
>
> thought I recommend deleting the line.

hmmm ... /thought/ this was the whole point of this addition

>
> Folks need to know the unit tile scale if wrapping the tiles around a
> cylinder or doing something like Jaime's wallpaper technique. Just
> setting up the switch is enough to provide the information assuming
> there is a mention in the documentation that is where the information is.
>
> I'm also a little unsure of the new additional scale up of <5,1,5>
> you've added just below. Feels large. Does it look OK with all 27 tiling
> patterns?

your addition ... didn't you test /all/ those out for yourself. that's 
why i threw this back into your court. some of the results looked 
questionable to me. as for scale <5,1,5> ... either that or move camera 
closer is all ... your code so do what you think is best

>
> Aside: There will be a similar set of 3 scalings for the pavement
> pattern, but I've just put in a pull request to add a pavement.pov
> example - so I'll go modify that pull request now instead of proposing
> wiki updates.
>
> Will you be putting in the tiling.pov pull request yourself, or would
> you like me to do it?

be my guest ...


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From: Jim Holsenback
Subject: Re: Proposed informational table for tiling pattern section.
Date: 26 Sep 2016 07:24:15
Message: <57e9055f$1@news.povray.org>
On 9/26/2016 5:52 AM, omniverse wrote:
> Something I was looking at by using that scene file was to find out how those
> patterns would repeat as, well, tiles. Noticing you were rotating the original
> tile to make 4 instances I wanted to see them side by side without rotation.

the rotation was a basic attempt to see if the single /scaled/ tiles 
indeed can be tiled and to me some do and some don't that is why i 
tossed back and hoped OP would respond. i'm missing the utility of this 
change

the original version so this scene file placed the pattern on a plane 
and the tiling of the pattern /was/ obvious.


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From: clipka
Subject: Re: Proposed informational table for tiling pattern section.
Date: 26 Sep 2016 12:54:01
Message: <57e952a9$1@news.povray.org>
Am 26.09.2016 um 11:52 schrieb omniverse:

> Had me thinking it might be one of those Penrose patterns before I realized
> those were said to be the last three. Of course I don't know what any of these
> are really, besides interesting!

The Penrose tilings are a family of curious tilings discovered by Sir
Roger Penrose in the 1970's.

The Penrose tilings have special properties that make them interesting
from both an aesthetic and mathematical point of view:

To the artist, the Penrose tilings have the rare property of exhibiting
pentagonal symmetry while at first glance appearing to be repetitive
(spoiler alert: they aren't; that would be impossible).

To the mathematician, the Penrose tilings have the rare property of
being /regular/ (meaning they follow a fixed set of construction rules
rather than randomly filling the plane with the tiles available) but at
the same time /aperiodic/ (meaning that they don't repeat -- no matter
what distance and direction you translate them, there are always tiles
that don't match up).

The three tilings are actually closely related; you could transform any
one of them into the other merely by applying a few simple substitution
rules.

There are other regular aperiodic tilings, but the Penrose tilings are
arguably the most aesthetic ones.


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From: clipka
Subject: Re: Proposed informational table for tiling pattern section.
Date: 26 Sep 2016 12:57:00
Message: <57e9535c$1@news.povray.org>
I've just noticed that at the bottom of the table on the Wiki discussion
page the tilings 25 to 27 are referred to as "penrose tiling"; since
they are named after Sir Roger Penrose, they should be written with an
uppercase P.


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From: William F Pokorny
Subject: Re: Proposed informational table for tiling pattern section.
Date: 27 Sep 2016 09:12:34
Message: <57ea7042$1@news.povray.org>
On 09/26/2016 07:15 AM, Jim Holsenback wrote:
> On 9/26/2016 5:38 AM, William F Pokorny wrote:
>
> hmmm ... /thought/ this was the whole point of this addition
>
...
> your addition ... didn't you test /all/ those out for yourself. that's
> why i threw this back into your court. some of the results looked
> questionable to me. as for scale <5,1,5> ... either that or move camera
> closer is all ... your code so do what you think is best
>
> be my guest ...

OK. I'll put in a pull request to update tiling.pov.

What we have today is OK & looks good if all people want to do is tile a 
floor with one of the patterns.

Where we want to do more with tiling and pavement patterns, it is often 
necessary to know the basic tile's scaling. It is this latter 
'information' we are aiming to make easily accessible somewhere.

These scalings do not necessarily mean repeatability of the unit square 
after scaling - though that is often the case.

I'll change penrose to Penrose in tiling.pov.

FYI. Jérôme created the tiling and pavement patterns and is our expert.

Bill P.


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From: Jim Holsenback
Subject: Re: Proposed informational table for tiling pattern section.
Date: 28 Sep 2016 05:07:57
Message: <57eb886d$1@news.povray.org>
On 9/27/2016 9:12 AM, William F Pokorny wrote:
> FYI. Jérôme created the tiling and pavement patterns and is our expert.

yes of course i'm aware of that ... when i said "your code" i was 
referring to the SDL (scaling) code not the application code and ....

FYI: I was the one who added the documentation for those patterns :-)


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From: omniverse
Subject: Re: Proposed informational table for tiling pattern section.
Date: 28 Sep 2016 06:20:00
Message: <web.57eb9932240564e0b1933f770@news.povray.org>
Jim Holsenback <spa### [at] nothanksnet> wrote:
> On 9/27/2016 9:12 AM, William F Pokorny wrote:
> > FYI. Jérôme created the tiling and pavement patterns and is our expert.
>
> FYI: I was the one who added the documentation for those patterns :-)

Obviously you and others have been very busy!

I hadn't seen the pavement patterns yet (that I could recall) so when looking
for a sample scene, not finding one, I thought the templates subfolders were
empty since no pov file showed up trying File|Open.

That had me looking at the actual subfolders to finally see everything via web
browser!

Almost speechless. Wow. Simply wow. I had no idea that much work had been done
on the documentation and examples. I was probably about to start a long hiatus
from POV-Ray during the time these things were beginning to develop for online
help.

Using POV less, mainly to keep a couple graphical charts going, is boring.
There's so much more to it!
Thanks to C. Lipka for getting me into UberPOV recently when I noticed it being
talked about.
Oh, and thanks for that Penrose explanation. I had seen something on TV about it
years ago, so knew of the person/name, but only remembered it as a geometric
curiosity.

A tremendous thanks to all for the efforts.

Bob


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